When we convert rolls for our customers we only use our large slitters that cut through the entire roll. However, for in house jobs that require only a short run of material we use the machine pictured below. This method is similar to the larger rewind slitters in that it cuts the material while it is being wound onto another roll. We just simply pull the material through versus rolling it onto another roll.

This type of table top slitter creates smooth clean edges and is often used to create pinstriping. I like it because I can take a 24″ wide roll and create a couple of 12″ wide by 10 foot rolls and then leave the rest of the 24″ roll intact. I purchased this machine from Ronan Tools and it is my understanding that they do not make the larger slitters anymore. The pictures below may help you if you wished to create your own from scratch. You could do it with some pvc pipe and some exacto knives.